The hydration state is important to all living organisms, Dehydration is a well-known phenomenon, in which a living body loses moisture to an excessive degree. Normally, the loss of body water will invoke thirst and thus induce drinking. However, tinder special conditions, such as the extremely hot and dry ambient atmosphere found in the, desert, the sensation of thirst might not be strong enough and the drinking rate thus induced may not be sufficient. The possible resulting dehydration can, in some cases, turn out to be fatal. In addition, over-hydration may occur during dialysis treatment of kidney diseases and may have serious consequences.